关于跨线程问题

Question

public partial class Form1 : Form
    {
      
        public Form1()
        {
            InitializeComponent();
          
        }

        delegate void settxt(object [] p);
      
        private void button1_Click(object sender, EventArgs e)
        {
            Thread th = new Thread(new ThreadStart(setTxtbox));
            th.Start();
        }
        private void setTxtbox()
        {
            this.Invoke(new settxt(delegate( object [] p) {
                a p0 = p[0] as a;
                a p1 = p[1] as a;

                textBox1.Text = p0.str + p1.str;

            }) ,new object[] { new a("hellow"),new a("word")}

           );
        }
    }
    class a
    {
        public string str;
        public a(string str)
        {
            this.str = str;
        }
    }

//出了什么问题呢，老说参数个数匹配不一致

Answer 1

Invoke方法的第二个参数是params object[] args，所以，你传入new object[] { new a("hellow"),new a("word")时编译器认为是你传入了两个参数，第一个是new a("hellow")，第二个是new a("word")，而delegte里面只要一个参数object [] p，这样就造成了参数个数不对。修改方式如下（这种情况编译器不会认为是两个参数）：

           object o = new object[] { new a("hellow"), new a("word") };
            this.Invoke(new settxt(delegate(object[] p)
            {
                a p0 = p[0] as a;
                a p1 = p[1] as a;

                textBox1.Text = p0.str + p1.str;

            }), o);

或者直接用两个参数的形式：

delegate void settxt(a p0, a p1);

this.Invoke(new settxt(delegate(a p0, a p1)
            {
                textBox1.Text = p0.str + p1.str;

            }), new a("hellow"), new a("word"));

Answer 2

是不是对Invoke传的参数个数，是根据我定义的delegate来传的？

Answer 3

是不是对Invoke传的参数个数，是根据我定义的delegate来传的？

Invoke方法重载，最后一个需要object数组。该数组的每一个元素应该就是你自定义委托的参数，所以：

 this.Invoke(new settxt(delegate( object [] p) {
                a p0 = p[0] as a;
                a p1 = p[1] as a;
                textBox1.Text = p0.str + p1.str;
            }) ,new object[] { new object[]{new a("hellow"),new a("word")}}
           );

---

ASP.NET Forum
Other Discussion Forums
FreeRice Donate
Issues to report
Free Tech Books Search and Download